Updated

Iraqi police opened fire on Sunni demonstrators in the country's north on Friday, killing one protester and wounding five others, police and hospital officials said. Fatal shootings have been comparatively rare during two months of anti-government rallies, and the death is likely to heighten Sunni demonstrators' anger against the Shiite-led government.

Policemen in the city of Mosul some 360 kilometers (225 miles) north of Baghdad shot at angry protesters demanding the release of a local tribal sheik who was arrested earlier in the day, the police officials said. The hospital officials confirmed the casualties. Both spoke anonymously as they were not authorized to speak to the press.

Minority Sunnis frustrated over what they claim is second-class treatment have taken to the streets across Iraq.

In Baghdad, security forces prevented worshippers from holding Friday prayers at a prominent Sunni mosque in northern Baghdad, a cleric there said.

"This is sectarian escalation by the government that should listen to the people's demands instead of pushing the people to extremism," said Dawoud al-Alousi, the imam of Abu Hanifa mosque in the primarily Sunni neighborhood of Azamiyah.

Al-Alousi and witnesses said security forces blocked traffic on roads leading to the mosque. He said it was the first time that prayers at Abu Hanifa have been cancelled during the current unrest.

Meanwhile, demonstrators in the western cities of Fallujah and Ramadi blocked the main highway to Jordan and Syria to perform Friday prayesr. Others gathered in the northern city of Samarra.

Sunnis have staged mass protests since late December following the arrest of bodyguards assigned to a Sunni finance minister, the latest action by the Shiite-led government that Sunnis believe target prominent members of their sect.

In a previous incident on Jan. 25, security forces shot dead five demonstrators, but in general the protests and the security response have been less deadly than those in other Arab countries over the past two years.

Iraq also witnesses attacks by hardline Sunni insurgent groups, some of whom are believed to be trying to exploit anti-government anger to re-establish themselves in strongholds from which they were driven by U.S. forces and allied anti-al-Qaida Sunni militias in 2006 through 2008. Insurgents have often targeted members of those militias, known also as the Sahwa, whom they consider traitors.

Gunmen shot dead five Sahwa militiamen late Thursday after abducting them from their house south of Baghdad, said police on Friday.

The bodies of three brothers and their two cousins were found in a nearby orchard with bullets in their heads, they said.